The Science of Self-Harm

Science sheds new light into self-injurious behavior, the brain, and early childhood experiences.

Self-harm or self-injury has generally been defined as self-destructive behavior without the intention to die. Although the behaviors that are classified under this definition have not yet been clearly defined, it has been generally accepted that the different and dynamic forms of self-harm lie along a continuum. This continuum ranges from mild forms of self-harm such as nail biting to more severe forms such as cutting and head banging. In between this spectrum lies impulse control disorders such as obsessive hair pulling (Trichotillomania) and obsessive skin picking (Dermatillomania).

Anxiety and physical and emotional abuse have been shown to be prevalent among people who self-harm (including skin-picking and hair-pulling). People who self-harm are often found to have higher rates of anxiety than those who do not and research has reported that most people who self-injure have a diagnosable anxiety disorder. Research has also reported that people who self-injure have reported higher rates of physical and emotional abuse in childhood than those who do not.

Childhood abuse can alter brain structure

Interestingly, research has reported that physical, emotional, and/or sexual abuse in childhood can actually alter neural structures that involve dopamine and serotonin. This is thought to happen indirectly through stress hormones released in the body due to the traumatic experience in childhood. These stress hormones are thought to interact with chemicals in the body to "trigger" different genes, such as the serotonin transporter gene, which then tells the body to develop its neurons in the brain a particular way.

Studies have shown that negligent parent-child interactions (including minimal touch, talk, and play) actually might alter neurons that process dopamine in the brain, leading to a condition known as "dopamine receptor supersensitivity". Studies have shown that people who are super sensitive to dopamine are more prone to anxiety and impulsivity.

For example, numerous studies have recently shown that people with Parkinson's disease, who are known to have dopamine receptor supersensitivity, displayed impulsive behaviors such as gambling and shopping when given dopamine agonists (medications that increase dopamine in the brain). These individuals also reported high rates of anxiety when given these medications.

In the case of self-harm, studies have suggested that dopamine receptor supersensitivity may be involved in the expression of different forms of self-harm. Some studies using Positron Electron Tomography (PET) scans, showed that individuals who self-injured showed dopamine receptor supersensitivity in their brains. This makes sense considering that anxiety and different forms of abuse have been associated with both self-harm and dopamine receptor supersensitivity.

Caffeine and self harm

Since research on stressful early parent-child relationships has demonstrated increased sensitivity to anxiety in adulthood by way of altered dopaminergic and serotonergic systems, it is questioned what type of effect caffeine might have on a person who has supersensitive dopamine receptors. This question arises because caffeine affects both dopamine and serotonin levels in the brain.

Caffeine is known to raise dopamine levels and produce stress and anxiety in certain individuals logically suggesting that individuals who have dopaminergic receptor sensitivity might be more vulnerable to anxiety and at-risk for self-injuring.

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